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Author Topic: ASHP on BBC You and Yours  (Read 11188 times)
clockmanFR
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« Reply #15 on: December 02, 2013, 10:15:42 AM »

I never actually got to ask him on how it actually worked, or if it was pump down, injection, then pump from another well pressure system, or the 1m hole diameter over 50m in depth stuffed full of 25mm pipes.

The guy was a bright Bio chemist, so practicalities were not pushed.


* HPb.gif (44.9 KB, 395x533 - viewed 248 times.)

* HP1b.jpg (54.8 KB, 395x533 - viewed 240 times.)
« Last Edit: December 02, 2013, 10:44:16 AM by clockmanFR » Logged

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dhaslam
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« Reply #16 on: December 02, 2013, 11:03:17 AM »

The 3 kW pump does sound like an  open loop system   but even then it seems  excessive.   It should be possible to change the system to  a CO2 collection system if the bore is deep enough.  The pipes  would be much smaller and could fit inside the existing  pipes.      A CO2 system doesn't  use any pump for the ground loop.   
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knighty
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« Reply #17 on: December 02, 2013, 11:26:44 AM »

maybe the 3kw pump is just the best pump they had available at the time

once the water gets flowing, the pump should us a lot less power?
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mike7
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« Reply #18 on: December 02, 2013, 11:38:41 AM »

I think it is appalling that this women ever had a ASHP fitted and could have a claim for misselling.
Ken

Quite so ... on the face of it. But the point of my post was to draw attention to how the BBC misunderstood or misrepresented the situation. If you read Sean's account (he was directly involved with the installation) you'll see that there's a very different untold story here.

A secondary point that irks me a touch is that when they talk of Air Source HPs they (and many others) really mean specifically air-to-water HPs. Air to air HPs (aka reversible aircon) are a different kettle of fish as they are much less  expensive to buy and fit, and for anyone not on mains gas they are quite likely to be a suitable addition to an existing heating system.
« Last Edit: December 02, 2013, 11:50:34 AM by mike7 » Logged
titan
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« Reply #19 on: December 02, 2013, 11:48:46 AM »


Sorry if I upset anyone flogging this stuff, but I will always bassh on about the Non sense-ical HP's.


Heat pumps are like wind turbines great in the right situation and very disappointing in the wrong one.  We are on a rural site with electricity only. A decent oil condensing boiler with storage tank, piping flue etc could easily cost 3000 the heat pump cost around 5000 with me doing the complete installation, ( I have a JCB)  ignoring any grant and the future RHI payment I think it is still a better solution, less mess no servicing etc and on sunny winter days some power to the GSHP from my PV. How well does it work, better than I calculated, the last 12 months for heating and 8 months DHW have used 2731Kwh, that is for an 8kW unit in a 300m2 house. Last year was the first year and I had the heating on 24/7 to get a benchmark I hope to improve on those figures as I optimise the UFH and heat pump settings.
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Other-Power
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« Reply #20 on: December 02, 2013, 11:53:28 AM »

on the flip side, take the 2000 saved and spend it on insulation, purchase you oil in the summer when prices are cheaper, have a massive tank of fuel so when the power cuts start you still have heating, you wont be saving much on carbon at the moment.

I agree that its completely the wrong thing for that lady to have but if she did promise to do insulation and she didn't, then there's a bit of fault there.

Cheers

Jon
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mike7
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« Reply #21 on: December 02, 2013, 12:26:07 PM »

From the Orkney website:- "There is only a 10 degree Celsius difference between the summer average temperature of 15C and the winter of 5C."
...due to closeness of sea and gulfstream, apparently. That makes air source slightly better there than for many other UK regions. I'd want to be sure about the outside unit's ability to tolerate salt, though.
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titan
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« Reply #22 on: December 02, 2013, 12:38:10 PM »

on the flip side, take the 2000 saved and spend it on insulation, purchase you oil in the summer when prices are cheaper, have a massive tank of fuel so when the power cuts start you still have heating, you wont be saving much on carbon at the moment.


Jon

It would be 800 as I got a 1200 grant but I can't get any more insulation in. Insulation thickness also has diminishing returns, I am  currently around three times better than current regs. You will still need electricity to run an oil boiler and any heating system with a pump. Oil did not drop much if at all last summer and is increasingly being targeted by thieves in rural area.
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skyewright
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« Reply #23 on: December 02, 2013, 02:16:51 PM »

Heat pumps are like wind turbines great in the right situation and very disappointing in the wrong one.  We are on a rural site with electricity only. A decent oil condensing boiler with storage tank, piping flue etc could easily cost 3000 the heat pump cost around 5000 with me doing the complete installation, ( I have a JCB)  ignoring any grant and the future RHI payment I think it is still a better solution
Sounds good to me. Off topic, but how did you go about sizing the system, especially deciding on the size & layout of the ground loop? Is there a handy design guide somewhere?

My impression from a couple of topics is that professional installs are heading towards working out the RHI benefit potential first, then calculating a price based on that, as opposed to design plus components plus labour plus reasonable margin.

BTW, I just popped along to the Navitron site to check their GSHPs & they've gone! There's still a GSHP page but at the point of writing this it only shows a flow switch. I'm sure there were pumps listed there only a short while ago, includnig a 3kW job? Maybe it's just a temporary glitch?
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Regards
David
3.91kWp PV  (17 x Moser Baer 230 and Aurora PVI-3.6-OUTD-S-UK), slope 40, WSW, Lat 57 9' (Isle of Skye)
Other-Power
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« Reply #24 on: December 02, 2013, 03:08:12 PM »

on the flip side, take the 2000 saved and spend it on insulation, purchase you oil in the summer when prices are cheaper, have a massive tank of fuel so when the power cuts start you still have heating, you wont be saving much on carbon at the moment.


Jon

It would be 800 as I got a 1200 grant but I can't get any more insulation in. Insulation thickness also has diminishing returns, I am  currently around three times better than current regs. You will still need electricity to run an oil boiler and any heating system with a pump. Oil did not drop much if at all last summer and is increasingly being targeted by thieves in rural area.

The way you have explained it, I thought it would be outside of MCS, but the grant does change it somewhat, I understand the running and pump needs electric but we are talking 200 watts not 2.5kW.  If your house is three times better then regs, why do you need air to water unit, would an air to air ASHP make more sense/cheaper still?

Jon
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Other-Power
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« Reply #25 on: December 02, 2013, 03:08:52 PM »

From the Orkney website:- "There is only a 10 degree Celsius difference between the summer average temperature of 15C and the winter of 5C."
...due to closeness of sea and gulfstream, apparently. That makes air source slightly better there than for many other UK regions. I'd want to be sure about the outside unit's ability to tolerate salt, though.

Dimplex do offer a coating of some sort on their units, not sure if other companies offer this?

Jon
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titan
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« Reply #26 on: December 02, 2013, 03:55:32 PM »


 Off topic, but how did you go about sizing the system, especially deciding on the size & layout of the ground loop? Is there a handy design guide somewhere?


There are many types of ground arrays and supporters of each type. A read through this forums heat pump section ( where there are a few relevant threads) may give some insight but then maybe not  Huh

After a lot of research I went for thinner walled larger diameter pipe in two single pipe loops at around 800mm depth but there are plenty of other options all claiming to be better.

Sizing the system is simple, work out the maximum heat demand for your property including DHW ( if required)  and size the pump and array  to suit that load, I don't think there is any other option now for an MCS installation.
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titan
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« Reply #27 on: December 02, 2013, 04:21:18 PM »


The way you have explained it, I thought it would be outside of MCS, but the grant does change it somewhat, I understand the running and pump needs electric but we are talking 200 watts not 2.5kW.  If your house is three times better then regs, why do you need air to water unit, would an air to air ASHP make more sense/cheaper still?

Jon

I said ignoring any grants or RHI so it made a fair comparison of the two systems. Oil boilers have spinning burners or pump pressured nozzles which need electricity as does the lift pump for the supply and any control valves in addition to the circulating pumps. So you will need a decent sized UPS to run a heating system in a power cut. I looked at ASHP but they are too noisy ( for my outside location) and are least efficient at low temperatures. A wet system is far better IMO for distributing heat than an air to air set up and also provide DHW. It also allows for a different heat source  at some time in the future. Any heat pump has to matched to the maximum heat demand and I think a GSHP will give better long term service but each to their own. 
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Other-Power
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« Reply #28 on: December 02, 2013, 04:55:48 PM »


The way you have explained it, I thought it would be outside of MCS, but the grant does change it somewhat, I understand the running and pump needs electric but we are talking 200 watts not 2.5kW.  If your house is three times better then regs, why do you need air to water unit, would an air to air ASHP make more sense/cheaper still?

Jon

I said ignoring any grants or RHI so it made a fair comparison of the two systems. Oil boilers have spinning burners or pump pressured nozzles which need electricity as does the lift pump for the supply and any control valves in addition to the circulating pumps. So you will need a decent sized UPS to run a heating system in a power cut. I looked at ASHP but they are too noisy ( for my outside location) and are least efficient at low temperatures. A wet system is far better IMO for distributing heat than an air to air set up and also provide DHW. It also allows for a different heat source  at some time in the future. Any heat pump has to matched to the maximum heat demand and I think a GSHP will give better long term service but each to their own. 

Might have a look over how much power a boiler uses again.

I would disagree that you need to size a heat pump to the maximum heat demand, many units have immersions attached for those very cold days, its a design consideration that can save a lot of money on capital.  Does MCS require units not to have an immersion to claim RHI?

I think you are double counting the benefits for your comparison of the two heat sources.  Doing some/all of the work yourself, saving money, and then also including a grant, to say there is only 800 in it isnt the situation that most people find themselves in when looking at the two heat sources.  For you situation, if you have insulated as far as you can then a GSHP might suit but on the most part, installing a cheaper heating option and spending the difference on insulation would be the better option IMO.  This to me, is the situation the lady in question had arranged with the installer and failed to keep her end of the deal, then complains the ASHP dosnt do what they said it would.

Bit like this wind turbine:

http://uk.finance.yahoo.com/news/the-48-000-government-wind-turbine-generates-5-worth-of-electricity-month-123141809.html

Jon
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dhaslam
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« Reply #29 on: December 02, 2013, 05:08:03 PM »

In a damp climate an air source heat pump should be covered.    They need about 100  cubic metres of air per kWh   but could still be located in a shed with plenty of ventilation.  

Ground source  arrays depend a lot on soil types and underground moisture levels.   There is a  quite a good list in the Ideal GSHP installations manuals.  They suggest 10-40 watts per metre of horizontal ground array  and  25 - 100 for vertical.     In country areas there are plenty of  well boring companies and  it should be possible to get a reasonable price for a moderately deep system and the saving  in running cost is quite significant for several degrees extra input temperature, particularly where winters are cold.        
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DHW 250 litre cylinder  60 X 47mm tubes
Heating  180,000 litre straw insulated seasonal store, 90X58mm tubes + 7 sqm flat collectors, 1 kW VAWT, 3 kW heatpump plus Walltherm gasifying stove
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